Update collections-methods.md

Ben-Wormald · web-flow · commit de33cf3afdeb · 2019-10-17T15:17:09.000+01:00
Move tail exception example to correct section
diff --git a/_overviews/scala-book/collections-methods.md b/_overviews/scala-book/collections-methods.md
@@ -210,6 +210,13 @@ scala> "bar".tail
 res3: String = ar
 ```
 
+Note that like `head`, `tail` will also throw an exception when called on an empty collection:
+
+```scala
+scala> emptyList.tail
+java.lang.UnsupportedOperationException: tail of empty list
+```
+
 
 
 ## `take`, `takeWhile`
@@ -240,13 +247,6 @@ scala> names.takeWhile(_.length < 5)
 res5: List[String] = List(joel, ed)
 ```
 
-Note that like `head`, `tail` will also throw an exception when called on an empty collection:
-
-```scala
-scala> emptyList.tail
-java.lang.UnsupportedOperationException: tail of empty list
-```
-
 
 
 ## `drop`, `dropWhile`
